Sources of biofuels


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Sources of biofuels

  1. 1. BIOENERGY 1. Biomass: sources, characteristics & preparation: • Sources and classification of biomass available for energy production. • Chemical composition and properties of biomass • Energy plantations • Preparation of biomass for fuel applications: Size reduction, Briquetting of loose biomass, Drying, and Storage and handling of biomass.Reference book:Renewable Energy Engineering and Technology: Principles &Practice, Edited by V. V. N. Kishore, 2009 T E R I, N. Delhi.Chapters12 to 15, pp 625 to 917.SOURCES: The material of plants and animals is called biomass.Bio-energy is energy derived from biomass. Before thedevelopment of technology based on coal, lignite, crude oiland natural gas (fossil fuels) bio-fuels were the sources ofheat energy. Woody biomass is product of forestry and trees fromdifferent agro-forestry activities of smaller intensity. Timber(used for commercial purpose) and fuel wood are obtainedfrom the forests besides minor forest produce. Commercialplantations like rubber and plants/trees that yieldhydrocarbon can be a source of byproduct fuel. 1
  2. 2. Agriculture yields by annual harvest a large crop residuebiomass part of which can be a source of rural biofuels.Plants that grow in wastelands are also potential energycrops. Nonedible oils from trees are a byproduct liquid fuel. Non -edible vegetable oils can be used as liquid fuels. Bytrans-esterification reaction between the oil and an alcohol inpresence of an alkaline catalyst, esters can be produced thatare potential substitute for diesel as engine fuel. Biomass that is used for producing bio-fuel may bedivided into woody, non-woody and wet organic wastecategories. The sources of each are indicated below. 2
  3. 3. Sources of three categories of biomass WOODY NON-WOODY WET ORGANIC (cultivated) WASTE FORESTS FOOD CROPS ANIMAL WASTES WOODLANDS CROP RESIDUES MANURE, SLUDGE PLANTATIONS PROCESSING MUNICIPAL SOLID (MULTI- RESIDUES WASTE PURPOSE TREES) HYDROCARBON NONEDIBLE OIL WASTE STARCH & PLANTS SEEDS SUGAR SOLUTIONS TREES FROM ENERGY CROPS: OTHER VILLAGE (SUGAR CANE INDUSTRIAL COMMON BAMBOO) EFFLUENTS LANDS (B O D)Animal manures and wastewaters containing organicputrefiable matter can be treated by anaerobic digestion orbiomethanation to produce biogas as a fuel. Starchy andsugar wastewaters can be substrates for fermentationprocesses that yield ethanol which is a potential liquid fuel. 3
  4. 4. BIOMASS CONVERSION METHODS FOR PRODUCINGHEAT OR FUELS:Controlled decomposition of low value biomass to derive itsenergy content in a useful form is the purpose of the bio-energy programs. Biomass energy conversion may give amixture of bio-fuel and. by product. Examples are givenbelow. Bio-fuels derived from biomass can be solid, liquidand gas fuels that can be used for combustion in speciallydesigned furnace, kiln and burners. PRIMARY SECONDARY CO- BIOMASS PRODUCT PRODUCT WOOD CHAR (PYROLYSIS) PYROLYSIS OIL WOOD CHAR PRODUCER (GASIFICATION) GAS ANIMAL BIOGAS (AN. FERTILIZER MANURE DIGESTION) 4
  5. 5. Bio-fuel production from primary biomass may utilize thermo-chemical, biochemical and catalytic conversion processes(see following table) Conversion process chosen dependson the properties of the primary biomass available. THERMOCHEMICAL BIOCHEMICAL CATALYTIC CONVERSION PYROLYSIS ANAEROBIC HYDROGENATION DIGESTION GASIFICATION FERMENTATION TRANS- ESTERIFICATION COMBUSTION HYDROLYTIC SYN.GAS ENZYMES PROCESS 5
  6. 6. Forest resources of India:India’s is sustaining 16 % of the world’s population and15 % of its livestock population on 2.47 % of world’sgeographical area and has just 1 % of world’sforests. o Forest area cover (i.e., the area notified as forest) in 1997: 76.52 million hectares, which is 23.28 % of the total geographical area of India. o The aggregate demand for fuelwood for the country in 1996 was 201 million tonnes, i.e., 213.8 kg per capita per year for a population of 940 million. The current sustainable production of fuelwood from forests is 17 million tonnes and from farm forestry and other areas is 98 million tonnes. There is a deficit of 86 million tonnes of fuelwood, which is being removed from the forests as a compulsion. o Forest resource base has tremendous pressure on it and availability is not catching up with demand for firewood. World Environment Day: June 5 o State Forest Departments and Community based organizations have Joint Forest Management Programs to prevent degradation and to regenerate forest areas. 6
  7. 7. Distribution of forest areas in States: o In Andaman & Nicobar area, forests occupy 86.9% of the total geographical area, whereas in Haryana, forests occupy 3.8%. o Arunachal Pradesh, Himachal Pradesh, Manipur, Mizoram, Nagaland and Tripura have over 50% of their land areas under forests while Gujarat, Jammu & Kashmir, Punjab & Rajasthan have less than 10%. The forest in other states range between 10 and 50 % of their land areas and the per capita forest area of India is 0.07 hectares.Causes of deforestation: o Exponential rise in human and livestock population puts increasing demand on land allocation to alternative uses such as agriculture, pastures, human settlements and development activities. o Insufficient availability of commercial fuels in rural areas as well as the lack of purchasing power of the rural poor and urban slum dwellers makes them dependent on firewood and wood char as fuels for cooking.Energy Crisis of Rural and Urban poor in India: o Nearly 75% of the rural population of India is dependent on bio-fuels (firewood, agricultural residues, and cow 7
  8. 8. dung) for meeting 80% of their energy needs. Similarly the urban poor, including the slum dwellers who constitute 25 – 30% of the urban population are heavily dependent on bio-fuels. This is because of their low purchasing power and limited availability of the commercial fuels-kerosene and LPG.Consequences of inefficient and high consumption ofwood biomass for energy: o Destroying biomass resources at a rate faster than that of their regeneration may lead to depletion of forests and desertification. o Forests, which are earth’s largest depository (sink) of carbon dioxide, diminish the green house effect. Growing gap between biomass consumption and regeneration leads to a crisis of sustainability.WOODY BIOMASS USE SHOULD BE A BALANCED & EFFICIENTONE o TECHNOLOGICAL INNOVATION ON BIOMASS MUST CONCENTRATE ON: IMPROVING ITS PRODUCTION, TRANSFORMATION AND APPLICATIONS FOR ENERGY. • WOOD BIOMASS IS AN ENDANGERED LIFE SUPPORT SYSTEM. 8
  9. 9. • IT SHOULD BE UTILISED IN A SUSTAINABLE WAY.TREES / WOOD: Leucaena leucocephala (Subabul) Acacia sp Casurina sp Derris indica (Pongam) Eucalyptus sp Sesbania sp Prosopis juliflora Azadiracta indica (Neem)HYDROCARBON PLANTS: Euphorbia group Euphorbia LathyrusOIL PRODUCING SHRUBS: Euphorbia Tirucali Soyabean Sunflower Groundnut 9
  10. 10. Environmental impact of biomass utilization for energy:In developing countries, trees are often cut down becausethey are the only source of fuel for the population. This canlead to environmental damage. The habitats of wild animalsare destroyed. Soil is eroded because tree roots are nolonger present to bind it together. This soil may be washeddown into rivers, which then silt up and flood. But thedestruction of trees and forests is a worldwide environmentalproblem with deforestation accounting for 18% of thegreenhouse effect today. New trees mustreplace the ones that are cut down if we are to protect theglobal climate and the lives of people in the developingcountries.Reference: Forests as biomass energy resources in India byB. N. Dwivedi and O. N. Kaul in Biomass Energy Systems,Edited by P.Venkata Ramana and S. N. Srinivas,British Council and T E R I, N. Delhi, 1996.Energy Plantation:Growing trees for their fuel value on ‘Wasteland’ or land thatis not usable for agriculture and cash crops is social forestryactivity. A plantation that is designed or managed andoperated to provide substantial amounts of usable fuel 10
  11. 11. continuously throughout the year at a reasonable cost maybe called as ‘energy plantation’ Suitable tree species and land with favorable climateand soil conditions of sufficient area are the minimumresource required. Depending on the type of trees, the treelife cycle, the geometry of leaf bearing branches thatdetermines the surface area facing the sun, the arearequired for growing number of would be evaluated.Combination of harvest cycles and planting densities thatwill optimize the harvest of fuel and the operating cost, areworked out. Typical calorie crops include 12000 to 24000trees per hectare. Raising multipurpose tree species on marginal lands isnecessary for making fuel wood available as well as forimproving soil condition. Trees for fuel wood plantations arethose that are capable of growing in deforested areas withdegraded soils, and withstand exposure to wind and drought.Rapid growing legumes that fix atmospheric nitrogen toenrich soil are preferred. Species that can be found in similarecological zones, and have ability to produce wood of highcalorific value that burn without sparks or smoke, besideshaving other uses in addition to providing fuel are the 11
  12. 12. multipurpose tree species most suited for bio-energyplantations or social forestry programs.AZADIRACTA INDICA (NEEM), LEUCAENALEUCOCEPHALA (SUBABUL), DERRIS INDICA(PONGAM), AND ACACIA NILOTICA (BABOOL) areexamples of tree species for the above plantations.AGRO-RESIDUES:Biomass Availability Coal equivalent[Year 2000] Million tons/year Million tons/yearRice straw 100 60Rice husk 30 20Jute sticks 25 10Wheat straw 50 38Cotton stalks 20 17Bagasse 30 25Molasses 05 03Coconut husk / 02 03shellSaw dust 05 06Other 33 18Total 100 200 12
  13. 13. Estimated biomass residue production in India - 2010Crop Area (Mha) Produce (MT) Residue R/P Type of (dry) (MT) Residue Straw, huskRice 46.1 118.8 213.9 1.8 StrawWheat 28.5 98.5 157.6 1.6 stalkJowar 5.3 6.1 12.2 2.0 stalkBajra 8.6 6.8 13.6 2.0 Stalk, cobsMaize 6.6 13.0 32.5 2.5 Seeds, wasteCotton 10.1 15.9 55.7 3.5 wasteJute 0.6 6.5 10.5 1.6Sugar Cane Bagasse, 5.5 463.5 185.4 0.4 wastesSource: Ravindranath et al, (2005) 13
  14. 14. Table: Estimated potential for biomass energy : 1015 J y-1 (1015 J y-1 = 320MW) Estimated total potential bio-fuelresources harvested per year for variouscountries(1978):Source Sudan Brazil India Sweden U.S.A.Animal Manure 93 640 890 18 110Sugar Cane 660 1000 430 --- 420Fuelwood 290 3200 420 160 510Urban Refuse 5 94 320 23 170Municipal 2 11 66 1 5SewageOther --- --- --- ---- 630Total Potential 1000 4800 2100 200 1800Present national 180 2700 5800 1500 72000energy consumptionRatio potential to 5.5 1.8 0.4 0.13 0.03consumptionRef: Vergara, W. and Pimental, D.(1978)’Fuels frombiomass’, in Auer, P.,(ed.),Advances in Energy Systems and Technology, vol.1,Academic Press, New York, pp 125-73 14
  15. 15. Estimated quantity of waste generated in India (1999):Waste QuantityMunicipal solid Waste 27.4 million tones/yearMunicipal Liquid Waste 12145 million liters/day(121 Class1 and 2 cities)Distillary (243 nos) 8057 kilolitres/dayPress-mud 9 million tones/yearFood and Fruit processing waste 4.5 million tones /yearDairy industry Waste 50 to 60 million litres / day(C O D level2 Kg/m3 )Paper and Pulp industry Waste 1600m3 waste water/day(300 mills)Tannery (2000 nos) 52500 m3 waste water/daySource: IREDA News, 10(3):11-12, 1999, V.BhakthavatsalamFor details of characterization of biomass and analyticalprocedures for determining properties, refer chapter 12,Renewable Energy Engineering and Technology: Principles &Practice, Edited by V. V. N. Kishore, 2009, T E R I, N. Delhi. 15
  16. 16. Properties of BiomassPhysical Properties: Moisture Content, Particle Size and Size distribution Bulk Density & Specific gravityProximate Analysis: Moisture Content Volatile Matter Fixed Carbon Ash or mineral contentChemical composition and heat content:Elemental Analysis: Carbon Hydrogen Oxygen Nitrogen SulphurHigher Heating Value: 16
  17. 17. Chemical Composition: Total Ash %, Solvent soluble %, Water Soluble %, Lignin %, Cellulose %, Hemi-cellulose %Wet and biodegradable biomass: C O D value & B O D value, Total dissolved solids & Volatile solidsBIOMASS PREPARATION FOR FUEL USE:Preliminary treatment of biomass can improve its handlingcharacteristics, increase the volumetric calorific value, andfuel properties for thermo-chemical processing. It canincrease ease of transport and storage.Examples: CHIPPING, CHOPPING, DRYING, GRINDING,BRIQUETTING ETC.Fuel wood requires drying in air and chopping for best resultin cook stoves. Saw dust requires drying and briquetting toincrease its bulk density. Industrial boilers require uniformlysmaller sizes of wood for feeding their furnaces. Predrying of 17
  18. 18. biomass to moisture levels of below 20% (oven dry basis)enhances efficiency of combustion in cook stoves andindustrial boilers. For production of high or medium pressure steam byusing biomass the best choice of equipment is the watertube boiler. It has a large combustion area surrounded bybanks of vertical water tubes, which makes it suitable forbiomass fuels. Biomass fuels have a high content of volatilematter and lower density and bulk density compared to solidfossil fuels; as a result , biomass fuels need a large space(relatively ) above the fuel bed to prevent flaring volatilematerial from impinging upon the chamber wall and causingdamage to it over a period of time. Shell boilers areunsuitable for biomass fuels because of the restricteddiameter of the furnace tube and high risk of damage to thetube wall by flame impingement. Additionally demand foruniform fuel quality and size by shell boilers are relativelystricter.Other types of end use equipment that are suitable for sizereduced biomass include cyclone furnaces, fluidized bedsystems and the controlled combustion incinerator. Cyclonesfurnaces are adaptable to use of wood waste s fuel. 18
  19. 19. Briquetting technologies:Reference: ’Biomass feed processing for energy conversion’P. D. Grover, in Biomass Energy Systems, Ed. P. VenkataRamana and S. N. Srinivas , T E R I and British Council, N.Delhi(1996) pp 187-192The proven high pressure technologies presently employedfor the briquetting of biomass are by the piston or the ramtype press and the screw or the extruder type machines. 19
  20. 20. Both the machines give briquettes with a density of 1-1.2gm/cc and are suitable as industrial solid fuels. The screwtype machines provide briquettes with a concentric hole thatgives better combustibility and is a preferred fuel. Thesebriquettes can also be more conveniently deployed in smallfurnaces and even cook-stoves than solid briquettesgenerated by a ram press.Biomass densification-A solid(fuel) solution. N.Yuvraj,Dinesh Babu, TERI, New Delhi. TERI Newswire, 1-15December, 2001, page 3. In India, briquettes are mostly made from groundnutshell, cotton stalk, saw dust, coffee husk, bagasse, mustardstalk and press mud. While the Southern region of Indiaproduces briquettes mostly from groundnut shell and sawdust, Western andNorthern regions produce bagasse, groundnut shell, cottonstalk, mustard stalk and press mud briquettes. As a recentaddition municipal solid waste is also densified for use asfuel in process industries (tea, tobacco, textile, chemical,paper, starch, tyre re-treading, tiles, etc) for thermalapplications. 20
  21. 21. Biomass & Bio-energy 14, no5-6, pp 479-488, 1998‘A techno-economic evaluation of biomass briquetteing inIndia’ A.K.Tripathi, P.V.R.Iyer and Tarachand Khandapal (I IT, N.Delhi) tarak@ces.iitd.ernet.inVarious types of raw materials used for briquetteing are:ground-nut shells, cotton stalks, bagasse, wood chips, sawdust, and forest residues. Pyrolysed biomass can also beused. Materials can be fine granulated, coarse granulated orstalky. Material may be dry or wet with various moisturecontent. After a material is dried and crushed the pellets maybe formed under pressure with effect of heat,Biomass & Bio-energy 18(3):223-228(2000)‘Characteristics of some biomass briquettes prepared undermodest die pressures’ Chin, O.C and Siddiqui, K.M,Universiti Sains Malaysia,31750,Perak, Malaysiakmust@hotmail.com1. Discuss the sources and major kinds of biomassavailable in India. How is the use of biomass for energyjustified? Explain biomass characteristics, propertiesand suitable energy conversion methods.2. For solid biomass used for combustion, what is thesignificance of Proximate and Ultimate Analysis and 21
  22. 22. HHV? Give typical values for saw dust, bagasse and ricehusk.3. Discuss the woody, non-woody and organic wastebiomass available in India as resource for ruralsupplementary energy / electricity.4. How is sustainable use of biomass as energy sourcepossible and justified?5. Explain biomass characteristics, properties andsuitable energy conversion methods. 22